Prevention of severe thalassemia in northeast Thailand: 16 years of experience at a single university center

Abstract

To demonstrate the performance of thalassemia prevention in northeast Thailand during 1993-2008. Retrospective data from 1422 at-risk couples who attended from January 1993 to December 2008 were studied. All couples were suspected at-risk couples based on initial screening using standard protocols. Three thalassemia carrier types including alpha(0)-thalassemia, beta-thalassemia and hemoglobin E were identified using standard methods. Data on prenatal diagnosis were collected. Of the 1422 positive-screened couples, 1254 (88.2%) were diagnosed as true-positive couples. After DNA analysis, 968 of 1254 (77.2%) resulted at risk for three types of severe conditions being hemoglobin E-beta-thalassemia disease (640/968, 66.1%), homozygous alpha(0)-thalassemia (304/968, 31.4%) and homozygous beta-thalassemia (11/968, 1.1%). The remaining 1.3% of the couples were at risk for more than one disease. After genetic counseling, prenatal diagnosis was performed on 756 couples (78.1%). The proportions of affected fetuses, thalassemia carriers and unaffected fetuses were 26.9, 50.0 and 23.0%, respectively. Implementation of a prevention and control program accompanying with a referral system for prenatal diagnosis is technically feasible in northeast Thailand and a large number of severe thalassemia diseases have been prevented during the past 16 years of operation.